A normal month’s supply of the pill contains one week’s worth of white placebos and three weeks of pink birth control pills.

"I looked at it and said, 'there could be unwanted pregnancies out there," said London Drugs vice-president John Tse told the CBC. "We felt it was important to let the patient know so there can be a judgment call from the patient."

Apotex has contacted wholesalers and retailers about the possible placebo batch but has not contacted customers directly, initially listing the recall as voluntary. Apotex describes itself as the largest generic drug manufacturer in Canada.

"It's unbelievable to me that they didn't do a public recall right away," she said. University student Emily Costello told the CBC. “What were the reasons that they had to go through the retail first?"

Tse said his company has reached out to about 350 customers. In addition, they are offering free pregnancy tests and morning after pills to anyone taking Alysena-28.

"We felt we need to go and look after our patients, because who would fight for our patients," he said.

The Globe and Mail notes that the Canadian government elevated the case to a level 1 emergency out of concerns over women who may be taking the pill for medical reasons.

The CBC says the batch was distributed to nearly every Canadian province with the shipments taking place between December 2012 and the first week of April.

For any Canadian users of Alysena-28, the code on the potentially altered packages is LF01899A.